Plasma processing systems (for example, physical vapor deposition (“PVD”) systems) are used to deposit thin layers of a target material onto a substrate or etch patterns into a target. Plasma processing systems generally include a radio frequency (“RF”) generator that transmits a continuous and/or pulsing signal to a plasma chamber. An RF match having a variable impedance is generally located between the RF generator and the plasma chamber. The RF match may be tuned, i.e., the impedance may be varied, to make the output impedance of the RF match be the complex conjugate of the plasma chamber's impedance. Tuning the RF match reduces reflected power from the plasma chamber and/or the RF match, thereby increasing the power transferred from the RF generator to the plasma chamber and into the plasma process.
Oftentimes the RF generator is run in pulse mode and transmits a pulsing RF signal to the plasma chamber rather than a continuous RF signal. Conventional RF matches, however, cannot be actively tuned while the RF generator is in pulse mode. In one existing implementation, the conventional RF match is tuned while the RF generator is run in continuous mode. Once the RF match is tuned, the impedance of the RF match is fixed, and the RF generator is switched to pulse mode. Although the plasma chamber impedance may vary while the RF generator is running in pulse mode, the RF match impedance remains fixed resulting in reflected power from the chamber. In another implementation, the conventional RF match may continuously follow the phase and magnitude signal from the RF generator, and tune according to an average power of the phase and magnitude signal. This causes the RF match to move to a non-optimum position.